Replace gnu-specific sed command with simple grep.

makealias was using a gnu-extension to sed addressing, replace that with a
simple (and more robuse) grep command. Also, found a bug in the public
header file that was leaving one symbol out of the process.

fontconfig/fontconfig.h

@@ -312,7 +312,7 @@ FcCacheNumSubdir (const FcCache *c);
 FcPublic int
 FcCacheNumFont (const FcCache *c);
 
-FcBool
+FcPublic FcBool
 FcDirCacheUnlink (const FcChar8 *dir, FcConfig *config);
 
 FcPublic FcBool

src/makealias

@@ -4,7 +4,7 @@ shift
 HEAD=fcalias.h
 TAIL=fcaliastail.h
 rm -f $HEAD $TAIL
-sed -n -e '/^FcPublic /,+1p' "$@" | sed -e '/^FcPublic /d' -e 's/ *(.*$//' |
+cat "$@" | grep '^Fc[^ ]* *(' | sed -e 's/ *(.*$//' |
 while read name; do
 	case $name in
 	FcCacheDir|FcCacheSubdir)